Thermal detector



FIG. 1 is a front perspective view of a thermal detector showing a new design;

FIG. 2 is a top view thereof;

FIG. 3 is a right side elevational view thereof (the left side thereof being identical);

FIG. 4 is a bottom plan view thereof; and,

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a thermal detector, as shown and described. 